Instructions for building Pdfium from tag android-7.1.2_r36 with modified makefiles. This library is used by PdfiumAndroid.

I recommend building on Linux (virtual machine will suffice), because Windows is officially not supported and there are many problems on newer versions of OS X.

You will need about 60 GB of free space.

• install git

• install OpenJDK 8

• install repo

• $ mkdir ~/android_src && cd ~/android_src or select any other path

• $ repo init --depth=1 -u https://android.googlesource.com/platform/manifest -b android-7.1.2_r36

  (detailed description available here)

• $ repo sync -c -j 6 and wait...

• clone this repo (or download zip with its content)

• replace makefiles in ~/android_src with corresponding makefiles from this repo

• apply the fixes for barteksc/AndroidPdfViewer#253 described here

• $ source build/envsetup.sh

• $ cd external/pdfium/fpdfsdk

• $ lunch and select architecture

• $ mma -j 6 and wait ~5 minutes

• library is available in ~/android_src/out/target/product/generic*/obj/lib/libmod*.so, copy it somewhere

• $ rm -r ~/android_src/out before next build

It worked for me, on a Ubuntu 16.04.4 64-bit VM I got from OSBoxes. Just had to configure apt and install git/JDK.